It is known to provide a printer as a self-contained unit having an inlet opening for a paper web to be printed, an outlet opening from which the paper web is to be discharged and means within the printer defining a path for the paper web in the course of which the paper web interacts with a data-transfer device which prints alphanumeric or other characters upon the paper web.
Such printers are generally associated with computers and/or terminals for data processing, word processing and computation purposes and can constitute an output device for the computer.
The paper web which is fed to the printer is available as a folded stack which has its leaves connected together at junctions at which the leaves may be readily separated when the stack is subjected to a bursting or other severance process. In the case of a tractor-fed printer, along one or both of the edges of the web, strips may be provided with perforations which can engage in sprocket wheels. These strips may be removed along score-lines or perforated zones as well.
Friction-fed printers need not use a tractor arrangement with perforated strips but may clamp the paper web between a platen and pressure rollers.
The printers may be dot matrix, daisy wheel, ink jet, thimble or spool printers. They may make use of thermal transfer, inked ribbons or bands or even dry-transfer image-reproduction techniques. Indeed, this listing is by way of illustration only and is not intended to be comprehensive or in any way limiting of the instant invention.
To assure a compact facility, it is common practice to provide a stand or table for the printer which simultaneously serves to supply the fanfold paper forming the paper web to the latter, e.g. from a shelf on the stand below the table upon which the printer is supported.
In European patent publication EP-Al 165,130, an arrangement is described in which the supply of the paper web is located below the printer in the support table, passes through an opening in the side wall of the support table to feed to the printer from the rear and then the paper web is directed upwardly through another opening in the upper surface of the table turned through about 180.degree. substantially parallel to another portion of the path of the web upstream from the latter opening to the printer.
Other systems for feeding a printer requiring relatively complex paths between a supply of the paper and the printer itself through, along and around a printer table are known as well. See for example PCT publication WO 85/01697 of 25 Apr. 1985.
In all of these cases, difficulties are encountered in threading the paper web through the table structure to the printer.
It may be mentioned that in all of these cases as well, there are various bends and turns in the path which can cause problems with respect to crimping, jamming and folding of the paper web if the latter is not fed with great precision along the path.
Since the paper must frequently be replaced or changed and often by untrained personnel and the process requires many manual operations and may involve different types of paths for different printers, the problem is pronounced an is of considerable concern in the workplace.